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In the human body, muscle is a remarkable tissue with some odd properties. For one thing, it turns chemical energy into motion and force. For another, it's very plastic or malleable. For example, if you do nothing, your muscles shrink. But if you work your muscles hard, they change shape and get bigger and stronger.

People have spent a lot of time and energy working out the best way to pump iron in a gym, so they can bulk up as quickly as possible. But what about immediately afterwards, when you've stopped pumping iron? It turns out that what you eat or drink in that time period after you finish pumping iron is crucial to laying down some muscle.

Overall, there are three main types of muscle in the body.

First, there's cardiac muscle, in your heart. It's in there for the long term. Basically, it starts working before you're born, and when it stops, you die.

Second, there's smooth muscle. It's found inside your gut, and makes up the walls of that 10 metres of tube that runs from your mouth to your anus. It pushes your food from your mouth to your anus by cleverly synchronized waves of contraction. You basically have very little control over how and when it contracts — it all works mostly automatically.

And third, there's the voluntary muscles of your skeleton, that you use to walk, run or swim, or put food into your mouth, or throw a ball. This is the muscle that the body builders try to bulk up. But the average citizen should also get involved.

Overwhelmingly, the scientific and medical studies show that we should pump a little iron, to keep us strong as we get older. In general, as you age, not only do you lose muscle mass, but the muscles you do have get infiltrated with fat, making them weaker. On average, adults in their 50s who don't do much exercise or walking lose about 150-200 grams of muscle each year. But this decline in muscle mass begins in adults in their 30s, if they don't specifically do any strengthening activities.

Weight training exercises add muscle bulk. If you used a microscope, you could see the individual muscle fibres getting fatter. But it has other effects as well.

One study showed that weight training in older people forces the muscles to remove damaged mitochondria and replace them with new ones. Mitochondria are tiny structures in virtually all of your cells that make energy. Like a furnace, they consume oxygen and make energy. And weight training in older people seemed to reset the muscles back to a younger, undamaged state.

So you've been to the gym, you've done the weights, then what?

Consuming the right kind of nutrition immediately after a workout can change how much muscle bulk you add. People have tried all kinds of stuff, from sugar drinks to protein powders right up to the illegal steroids — which can indeed add muscle bulk, but have all kinds of dangerous side effects.

One surprising contender has turned out to be plain old milk. One study on men showed that over a 10-week period, if they drank just two cups of skim milk after each muscle workout, they would gain almost twice as much muscle as if they drank soy drinks with the same amount of protein.

Another study studied 20 young women (yes, unfortunately, it is a small sample size). Over a 12-week period, they worked out for an hour a day, five days a week. They did leg work, as well as upper body pushing and pulling work — always under close supervision by expert trainers. After each workout, they drank a litre of either fat-free milk, or a carbohydrate drink. As compared to the carbohydrate drinkers, the milk drinkers put on an extra 1.9 kilograms of muscle and lost some fat so they didn't increase their body weight — and also were stronger than the carbohydrate drinkers.

A surprising advantage of carrying a little extra muscle is that, even at rest, it burns up more energy than fat — so muscle helps keep your weight down.

Comments (38)

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Jonny :

08 May 2012 12:39:18pm

Totes cool. I put on a fair amount of muscle over the past year by doing weights, then had surgery rendering me couch bound for the past six weeks. I've lost a bit of muscle but have not put on weight (fat) so it's helped me keep slim for sure, burning energy while I push through the fifth season of dragon ball haha.

Deniso :

10 May 2012 6:23:58am

I learned that even if you don't feel like eating when you are sick, you still should not fast. Without food, our bodies will burn muscle before fat, because it is easier to metabolize. An article on how and what is metabolized would be helpful.Denis

vic :

10 May 2012 7:13:52pm

Deniso...wrong...wrong evolutionary history...and all animals...who are smarter than us ...never eat when they are sick...periods of regular fasting has been shown scientifically to provide brain growth, better health and longer lives..

Rob :

Jeremy :

13 May 2012 4:17:07pm

Shouldn't matter what flavor it is. Flavored milk in general should be more helpful, because the added sugar (sugar being a high GI carbohydrate) will help refuel your muscles and also assist the mechanism by which the milk protein enters the muscle.

But there should be no difference between chocolate milk and, say, strawberry flavour; there's effectively no caffeine in the chocolate milk, so it can't be that.

Stu :

Jeremy :

13 May 2012 4:20:21pm

Lol. Pretty much the only difference between skim milk powder and protein powders is that the protein powders have the carbohydrates removed; IE, the lactose.

There's still a little bit in whey protein concentrate, but it's minimal. Depending on how severe your intolerance is, you may not have any issues with it. If you do have issues, use whey protein isolate; it's a little more expensive, but not too much.

Rippedrooster :

09 May 2012 5:56:10pm

this isnt new the research and subsequent study had come to light some time ago but it is interesting to see the mitochindria reset with training regardless of the ageing process.I have always held to the beleife that if you keep placing stress on the body it will adapt.Basically keep up the physical demands and it will respond. The milk post training realy puts paid to protein bars, powders and the like a billion dollar industry based on missinformation.

Neddy North Coast :

09 May 2012 8:16:51pm

So wha' happen' to plain old-fashioned full-cream, unhomogenised milk (which is making a comeback in the supernmarkets)? You know, the stuff that anyone over 40 used to drink whenever they needed a "drink"? From where I sit, it didn't seem to destroy a generation.

mike :

Stu :

10 May 2012 7:56:07pm

In a study from Cree et al. Med Sci Sports Exerc. 2006 Apr;38(4):667-74. Milk ingestion stimulates net muscle protein synthesis following resistance exercise. Whole milk (3.25% fat) stimulated more protein synthesis than did skim or the same amount of skim to be equivalent energetically (i.e., more protein). So perhaps there is something to full fat milk? But no, it doesn't have to be skim milk!

Alex :

Katherine :

10 May 2012 11:54:24pm

So, why is the protein from milk more effective in building muscle than from a whey protein shake? Does it have to do with how quickly it is absorbed? Does it also have to do with the type or amount of carbohydrates absorbed?

Bill :

12 May 2012 2:36:16am

The article says soy protein, not whey. Whey is much more effective as far as how quickly it is absorbed, and is an overall better protein than soy. Milk contains a protein known as casein that releases slowly in the body, allowing adequate protein for the next 3-4 hours. Being an experienced weight lifter myself, I recommend whey protein mixed with milk immediately after a workout.

Jeremy :

13 May 2012 4:23:39pm

Katherine, milk proteins are made up of whey protein and casein protein.

Whey protein is more rapidly absorbed, hence it is usually what is consumed immediately postworkout. However, some recent studies indicate that adding casein to your whey shake can actually improve muscle synthesis.

Charlie :

11 May 2012 9:53:38am

You know its funny, all the old time strongman used to drink gallons of milk. There's a program somewhere called super squats where they do 20 rep squats and drink a gallon of milk a day. The old timers had it right and science is catching up it seems! I bulked up using this method and even documented the progress on my site: Charliefatloss.com

I'll say though the one downside to drinking so much milk now days is all the pasteriuzation and homogenisation. The old timers drank it raw.

GOLDIE Toor :

13 May 2012 3:50:16pm

100 % agree with Charlie. The Old Timers were more stronger than todays generation. I still follow heavy squats n full cream milk. I never gained any fat in my 30 years but just bulk up my all thigh,chest,triceps , biceps n forearm muscles. I love this schedule so much n feel so pumped up after workout. Got it from my father. He is 60 yrs old n has no fat at all. He use to be a wrestler in his young days. There is no short-cut to success but pure hard work in a gym.

august :

Nemesis :

12 May 2012 6:33:29am

Tradies drink loads of flavoured milk.Id consume 3 pints of iced coffee a day which was skim milk with artificial sugar.Cereal at 5:30 in the morning just isnt fun. Funny enough even though Ive not been on the tools for years my body hasn't changed much in fact I got heavier.Near the end 100 70kilo limestone blocks and a tonne of sand was common each day. Maybe the body hangs onto the muscle tissue in case I go back to work. 174cm 89kilosThe scales at the shops said I was obese.